 Did you hear that wheezing sound while he was breathing? Well, that's because this poor little boy suffers from a chronic disease called asthma. Unfortunately, this disease has no cure. It's a disease where his airways becomes very narrow and it becomes difficult for the free flow of air in and out from his lungs and thus causes that wheezing sound. And the narrowing of these airways or the bronchioles happens in response to certain triggers. Now what are those triggers? I have made few illustrations which I think will help you to remember them. The first trigger is induced by common allergens. The common allergens are dust particles or pollen from flowers. It could also be feathers or animal dendres. And apart from these allergens, common cold or bronchitis like normal infections caused by microbes can also trigger asthma in a person. Or we can talk about irritants, the very common one is the tobacco smoke, or very high pollution in the air, or fumes from your favorite perfume or cleaning products. And apart from that, the exercise induced asthma is a thing. You must have seen in movies that a person running very fast in a trade meal suddenly collapses and then he rushes to a pump kind of thing which he shoves in his mouth and then relaxes after some time. Those are kind of exercise induced asthma attacks. And apart from that stress and anxiety, certain drugs or sometimes even crying or you won't believe sometimes very heartedly laughing can also be a trigger for asthma. So what exactly happens to an asthma patient? Well in an asthma patient, the immune system is hypersensitive. We also call it the hypersensitivity. It is nothing but the chaotic immune response in the lungs, especially in the bronchial tubes causing them to narrow down. Not just the bronchial tube muscles but also the cartilaginous rings that surrounds them. So let's have a close look at these bronchial tubes. We will enlarge one and here is a section of the bronchial tube and as you can see it has a smooth muscle lining on the inner side and the outside is called the apithetium. And again on the inner side of the smooth muscles we will have a mucous lining, we will have a thin mucous lining which is quite normal in a normal lungs. And then we will have immune cells as well. Let's just write IC, immune cells, we will have immune cells as well to take care of anything foreign or anything not good for our body that might enter through our respiratory tract. So these immune cells will take care of that. Now let's assume that the dust particles enter the airways of a healthy human who is non-asomatic. When it enters first it will encounter the mucous layer, our mucous layer will hold a lot of dust and will not let it pass through the epithelial layer but even if it does then there is our immune cells sitting there, right there as our bodyguard. It will engulf it, secrete chemicals into it and neutralize those dust particles and that is the end of the whole dust story inside our body. But let's say this is the respiratory tract of an asthma patient, okay? Then they will have activated mast cells which is again a type of immune cells just under the epithelial layer. Now what's so unique about it? Well the moment the dust particle comes in contact with this mast cell it will burst and then create an immunological emergency situation inside the body. Now I won't detail how these mast cells get activated in an asthma patient because I have made a detailed video on allergy where I have mentioned the sequence of events leading to the activation of mast cells. So I encourage you to go and look for that video in the Khan Academy website, okay? Now coming back to this aggressive mast cell. What happens when it bursts? So as you can see mast cell has released all its content outside and mast cells generally are very granular. They have granules inside which contains a lot of toxins and as they release all these toxins outside it creates a havoc in the area. The most potent toxin that it releases is a chemical called histamine. Now histamine has a lot of different actions. The one that mostly affects asthma patient is their capacity to stimulate the nerves that connects the smooth muscles causing it to constrict, okay? So the first thing it does is smooth muscle contraction and the next thing it does is that it invites more mast cells or more immune cells I should say into the area causing the severity to increase, okay? And then it stimulates the cells that secrete mucus to produce more mucus. So imagine a condition where the airways are constricted because of these smooth muscle contraction and on top of that the mucus is overproduced, further reducing the space inside the airways and thus making the bronchial tubes look somewhat like this. And do you see there is a very little space, a tiny passage for the air to flow in and out which leads to coughing, wheezing sound while breathing, feeling tightness in the chest and even shortness of breath. That is why asthma patients seems as if they are panting and that is what it means. Asthma comes from a Greek word which means panting and as we discussed in the beginning of the video there is no cure to asthma yet. So what should an asthmatic patient do? The first thing he needs to do is to recognize his trigger. What triggers his asthma attack? And the moment he recognizes his trigger he should try his level best to avoid that trigger. But sadly with the increase of air pollution and dust in the environment a person cannot avoid these triggers no matter how hard he tries. But the good news is that today we have medicines in the market that provides instant relief to the airways. We call them bronchial dilators that dilates the bronchial tube. It contains anti-inflammatory drugs that reduces the inflammation in the airways. But if this doesn't help then there are certain intravenous injections which works rapidly in reducing the inflammation. And also certain lifestyle changes and regular deep breathing exercise is found out to be very effective against any pulmonary disorder. So even though there is no cure to asthma with proper diagnosis and early diagnosis, proper medications, healthy lifestyle and most importantly by avoiding the asthma causing triggers, an asthmatic patient can also live a long normal and healthy life.